Suspension for a surface maintenance appliance

ABSTRACT

An improved suspension system for coupling a surface maintenance tool or appliance to a surface maintenance machine is disclosed. In preferred embodiment, the suspension system includes a 4 bar linkage which permits the surface maintenance tool to be raised and lowered relative to the surface maintenance machine into selective contact with the floor surface, a spring assembly transferring spring force to the surface maintenance tool, and a selectively controllable actuator connected to the spring assembly for controlling a level of the spring force so that a controlled level of surface maintenance tool work is performed upon the floor surface.

RELATED APPLICATION

[0001] This application claims the benefit of priority of U.S.Provisional Patent Application No. 60/292,675, filed on May 21, 2001,the disclosure of said application being incorporated by referenceherein.

FIELD OF THE INVENTION

[0002] The present invention relates generally to surface maintenance orconditioning machines, and particularly those machines employing one ormore surface maintenance or conditioning appliances or tools thatperform one or more tasks including, among others, scrubbing, sweeping,and polishing or burnishing. The more specifically, the presentinvention is particularly directed to a suspension system for a surfacemaintenance appliance, and specifically a burnishing assembly.

BACKGROUND OF THE INVENTION

[0003] Surface maintenance machines that perform a single surfacemaintenance or surface conditioning task are, of course, well known.Surface maintenance machines are generally directed to applications suchas floor surfaces, or simply floors. The term floor, as used herein,refers to any support surface, such as, among others, floors, pavements,road surfaces, ship decks, and the like.

[0004] Commonly floor or surface maintenance machines are constructedhaving a single surface conditioning appliance or system so as to onlysweep, others to scrub, while still others only to polish or burnish. Itis of course possible to construct a single surface maintenance machineto perform one or more of the aforementioned surface maintenance tasks.

[0005] One example of a multi-task floor conditioning machine isdisclosed in the U.S. Pat. No. 3,204,280, entitled, “Floor Cleaning &Waxing Machine,” issued to Campbell, the enter disclosure of which isincorporated by reference herein in its entirety for any and allpurposes. Another is disclosed in U.S. Pat. No. 4,492,002, entitled,“Floor Cleaning Machine,” by inventors Waldhauser, et al, the entiredisclosure of which is incorporated by reference herein in its entiretyfor any and all purposes. Disclosed therein is a forward sweeperassembly followed by a scrubber assembly that is followed by a squeegeeassembly.

[0006] Yet, another example of a multi-task floor conditioning machineis disclosed in a PCT application having publication WO 00/74549,published Dec. 14, 2000, entitled, “Floor Cleaning Machine,” byinventors Thomas, et al, the entire disclosure of which is incorporatedby reference herein in its entirety for any and all purposes. Themachine disclosed therein performs the task of sweeping, scrubbing, andburnishing, and includes a squeegee assembly in combination with avacuum system for removing cleaning solution from a floor subsequent toa cleaning and scrubbing operation.

[0007] As illustrated in WO 00/74549, thereshown is a single unitarywalk-behind machine that is transportable across a floor. Successivelyattached to the machine, from front to back, are independent floormaintenance systems. At the forward section of the machine is a sweepingsystem. At the rearward section of the machine—machine steeringcontrol—is a burnishing system. In between the sweeping system and theburnishing system is a scrubbing system including forward scrubbingbrushes coupled to a cleaning solution dispensing system and rearwardfollowing squeegees coupled to a liquid vacuum system for recoveringexpended cleaning solution.

[0008] Burnishing systems generally include a scheme for controlling thedegree of burnishing applied to a floor surface depending upon the typeof floor surface intended to be burnished. Burnishing systems well knownin the art commonly include a driver assembly which includes a workingappliance or tool such as a pad or brush affixed to a driver that isrotatably driven by a driver motor. The driver assembly of theburnishing systems of the prior art have been selectively raised andlowered by an actuator so as to achieve an intended force or pressureagainst a floor surface intended to be polished or burnished.

[0009] Scrubbing systems are analogous to burnishing systems, and arealso well known in the art. Scrubbing systems commonly include a driverassembly including rotatable scrubber in the form of a brush, pad, orthe like, and a scheme for controlling the degree of scrubbing appliedto a floor surface depending upon the type of floor surface intended tobe scrubbed. Too much scrubbing of course may deleteriously affect thefloor surface requiring further maintenance. The scrubber driverassemblies for scrubbing systems, like burnishing systems, are of coursewell known in the art and commonly include one or more rotatable brushesdriven by a driver motor affixed to a scrubber head. Scrubber heads ofthe prior art have been selectively raised and lowered by an actuatorcoupled to the driver so as to achieve an intended force or pressure ofthe brush against a floor surface intended to be scrubbed. Examples ofthe latter are taught in U.S. Pat. Nos. 4,757,566; 4,769,271; 5,481,776;5,615,437; 5,943,724; and 6,163,915, the entire disclosures of which areincorporated by reference herein in its entirety for any and allpurposes.

[0010] Common to some control systems of the aforementioned prior artpatents is the employment of a current sensor that monitors the currentdrawn by the driver motor. In some of the aforementioned systems of theprior art a “pressure sensor” is employed that is representative of thepressure of the scrubber head against the floor. Still others attempt tocontrol torque load on the motor indicated by the sensed motor current.

[0011] Sweeper systems are also analogous to burnishing systems. Sweepersystems commonly include a rotatable sweeper system brush driven by adriver motor. Like burnishing and scrubbing systems the sweeper systembrush may be lowered and raised relative to a floor, which may more orless affect the floor surface.

[0012] Commonly, floor conditioning machines are powered by arechargeable battery supply. Of course, the battery voltage applied tothe various floor conditioning systems or appliances, and particularlyto the driver motor, will decay in relation to the energy discharged bythe battery and the total time of discharge. With respect to burnishingsystems, the mechanical burnishing power delivered to the floor istherefore dependent upon the voltage and current delivered to the drivermotor.

[0013] Burnishing appliances or systems on such floor maintenancemachines have several factors that place design demands on thesuspension system from the floor maintenance machine that are suspended.This is so since commonly the burnishing pad is somewhat surrounded inpart by peripheral portion of the driver and is surrounded by anattached skirt extending from peripheral portions of the driver—theskirt preventing dust and debris from being injected into theenvironment. In operation, upon powering of the burnishing assemblydriver motor, a vacuum is established within the chamber formed by theburnishing system driver and skirt. This in turn causes a vacuum whichtends to pull the burnishing assembly toward the floor. This vacuum maybe controlled by way of providing breather vents or ports in the skirt.

[0014] It should be understood that as the burnishing assembly suspendedfrom the frame of a floor maintenance machine is pulled toward the floorby the aforesaid vacuum greater load upon the driver motor results aswell increased working power or force against the floor results, themagnitude of which is dependent upon the type of floor surface intendedto be burnished or polished. Driver motor load current controllers knownin the prior art burnishing systems or scrubber systems, may of coursebe employed to more or less yield substantially controlled working poweror force against the floor surface, as well as prevent drive motor burnout.

SUMMARY OF THE INVENTION

[0015] An object of the present invention is to provide a suspensionsystem for a floor maintenance appliance suspended from a frameassociated with a floor maintenance machine.

[0016] An object of the present invention is to provide a suspensionsystem for burnishing appliance or assembly suspended from a frameassociated with a floor maintenance machine.

[0017] A variable load suspension system has been disclosed for varyingthe work force of a surface maintenance appliance upon a surfaceintended to be affected. In one exemplary embodiment, a seriescombination of an actuator and a spring assembly is coupled to a frameat one end, and the other end thereof is coupled to the surfacemaintenance appliance by way of an appropriate linkage. In the preferredembodiment of the invention, the spring assembly, and specifically thespring, generally extends in the direction of transport of the surfacemaintenance machine 10, and the actuator causes motion transverse to thesurface intended to be affected.

[0018] The actuator and driver motor of the surface maintenanceappliance are intended to be controlled by any of the aforementionedcontrol systems known in the art as well as others without departingfrom the true spirit and scope of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0019]FIG. 1 is a side view of a walk behind surface maintenance machineemploying a suspension system in accordance with the present inventionfor suspending a burnishing system.

[0020]FIG. 2 is a partial perspective view of the suspension systemassembly in accordance with the present invention.

[0021]FIG. 3 is a side view showing further details of the suspensionsystem assembly illustrated in FIG. 2.

[0022]FIG. 4 is top plan view illustrating suspension system componentsin accordance with the present invention.

[0023]FIG. 5 is a schematic block diagram of an exemplary embodiment ofa control system for a floor maintenance appliance for controlling thework output delivered to a floor surface.

DETAILED DESCRIPTION OF THE INVENTION

[0024] Illustrated in FIG. 1 is walk behind surface conditioning machine10 in accordance with the present invention. A burnishing assemblygenerally indicated by numeral 100 is suspended from a frame 20 by wayof a suspension system assembly in accordance with the present inventiongenerally indicated by numeral 200, and particularly illustrated in FIG.2 as will be described in further detail herein. FIG. 1 graphicallydepicts the available range of motion of the burnishing head or assembly100 when coupled to the frame in accordance with the present invention.Namely, a transport position 101, lowered operating position 102, andpad changing position 103.

[0025] Illustrated in FIG. 2 is a perspective view of the suspensionsystem 200 in accordance with the present invention. In FIG. 2,burnishing assembly 100 has been omitted. Suspension system 200 includesan actuator 220 pivotally coupled to frame 20 through coupling member224, and having an actuator rod 222 pivotally coupled to a springassembly 400 (not shown in FIG. 2, shown in FIG. 4). Spring assembly 400is coupled to a 4-point or four parallel bar linkage system 215 throughcoupling brackets 250L and 250R.

[0026] A pair of mounting bracket 210L and 210R is intended to berigidly attached to the burnishing assembly driver member 110 upon whicha driver motor is generally mounted.

[0027] Burnishing assembly 100 is coupled to frame 20 by way of the4-point or 4-bar linkage 215 including bars 230L, 230R, 240L, and 240R.Ends 232L, 232R, 242L, and 242R are pivotally coupled to frame 20 (notshown) by way rotatable mounted pins, bolts, or the like mounted throughapertures 234L, 234R, 244L, and 244R, respectively. The four pointlinkage system is of course well known for generally lifting andlowering an assembly with generally transverse movement relative to theground plane upon which the assembly may rest. In other words, permitsvertical movement while fixed in a lateral position relative to areference frame, namely the frame 20 of the surface maintenance machine10.

[0028] Suspension coupling bracket 250L has a first end 252L rigidlysecured to bar 240L by way mounting bolts 253, welding, or the like. Theother end of bracket 250L is pivotally coupled to one end of springassembly 400 as will subsequently be described in detail below.Similarly, bracket 250R has a first end 252R rigidly secured to bar 240Rby way mounting bolts 253 (not shown) or the like. The other end ofbracket 250R is also pivotally coupled to one end 410 of spring assembly400, and is substantially identical to suspension coupling bracket 250Lbut is substantially hidden from view in the figures.

[0029] Spring assembly 400 is further described in FIG. 4. Asillustrated in FIG. 4, spring assembly is essentially a preloaded drawspring well known in the art having a helical spring housing 420enclosing, in part, helical spring 410 with rod 430 passingtherethrough. One end 423 of housing 420 is pivotally coupled toactuator rod 222. The opposite end of rod 430 is affixed to pin assemblymember 440 by way of a threaded bolt 443, or the like. One end of spring410 is coupled to an anti-rotation plate 445 having extending tabs 447protruding through slots 446 of housing 420. The other end of spring 410engages housing end member 441 of housing 420 through which rod 430passes therethrough.

[0030] Pin assembly member 440 includes a pair of pins or rod shapemembers 43 IL and 43 IR intended to be pivotally coupled to suspensioncoupling bracket end members 253L and 253R of suspension couplingbrackets 250L and 250R, respectively. As illustrated in the figures, rodshaped members 431 pass through, in part, arcuate slots 255L (255R notshown). These slots may be omitted as their function provides forobtaining the appliance assembly position identified as numeral 103 inFIG. 1 while maintaining pivotal coupling. It should also be noted thatsuspension coupling brackets 250L and 250R are somewhat “s-shaped” so asto permit unobstructed movement of the 4-point suspension system, whileat the same time permit 4-point suspension system to be affected, inpart, by the combination spring assembly 400 and actuator 220.

[0031] Actuator 220 includes a mounting member 224 for pivotallycoupling actuator 220 to frame 20. Similarly end member 223 of actuatorrod 222 is pivotally coupled to housing end member 423 by way of anysuitable pivotal coupling, for example a travis pin assembly or the likeas indicated by numeral 425.

[0032] In an exemplary embodiment of the invention, draw spring assemblymay have a free length spring of 29 inches, an installed length of 15inches (compressed spring) with a 20 lbs.-inch rate of spring force. Itis of course should be understood by those skilled in the art that thesize of draw spring assembly 400 may be embodied by way of a wide arrayof physical sizes depending upon the weight of the burnishing assembly,and the available room and cost considerations associated with thesurface maintenance machine 10.

[0033] In operation of the suspension system of the present invention,in the actuator retracted position, the burnishing assembly is themachine transport position indicated by numeral 101 in FIG. 1 and theassembly is away from the floor surface.

[0034] In the “operate position,” the actuator is extended apredetermined amount until the burnishing head makes contact with thefloor surface while under the influence of the draw spring assembly 400.In turn the actuator 220 and burnishing head driver 110 motor may becontrolled to achieve regulated work force upon the surface intended tobe affected. Actuator 220 is selectively controlled during operation toadjust the degree of spring compression, and hence the degree of springforce transferred by spring assembly 400 to burnishing assembly 100.Actuator 220 may be a hydraulic actuator (not shown) or other knownactuation device appreciated by those skilled in the relevant arts.

[0035] The present invention provides a horizontal packaging techniquefor achieving variable spring load in the vertical direction of asurface maintenance assembly or appliance, for example burnishing,scrubbing, waxing assemblies, and the like.

[0036] A variable load suspension system has been disclosed for varyingthe work force of a surface maintenance appliance upon a surface. Aseries combination of an actuator and a spring assembly is coupled to aframe at one end, and the other end thereof is coupled to the surfacemaintenance appliance by way of an appropriate linkage. In the preferredembodiment of the invention, the spring assembly 400 generally extendsin the direction of transport of the surface maintenance machine 10(generally parallel with the surface), and the actuator causes motiontransverse to the surface intended to be affected.

[0037] It should be recognized that alternatively, the positions ofactuator 220 and draw spring assembly 400 could be interchanged asshould be recognized by those skilled in the art.

[0038] In accordance with another aspects of the present invention,brackets 210L and 210R are provided with arcuate slots 577 whereby pinscoupling bar members 230L and 230R may be lifted upward from points 213Land 213R. With the arcuate slots 577 and corresponding slots 255L and255R in coupling brackets 250L and 250R respectively, the entiremechanism may be lifted. Locking members 280L and 280R are provided witha slot so that bar members 250L and 250R may be pivotally coupled tomembers 280L and 289, respectively, permitting the assembly 100 to beraised to pad changing position as indicated by numeral 103 in FIG. 1.

[0039] Referring to FIG. 5, a schematic block diagram is illustratedrepresenting one exemplary embodiment of a control system for a floormaintenance appliance that controls the work output delivered to a floorby a rotatable work tool, such as a polishing pad, a scrubber, a brush,etc. Such a control system may be utilized in conjunction withembodiments of the present invention to control linear actuator 220.Additional aspects of this control system are disclosed in U.S. patentapplication Ser. No. ______, filed on May 21, 2002, entitled “ControlSystem for a Floor Maintenance Appliance,” having a common assignee withthe present application, and being incorporated in its entirety byreference herein. In FIG. 5, a floor maintenance assembly 10 isconfigured as a burnishing system suspended from a frame 22 associatedwith a floor maintenance machine (not shown) by way of an actuator 20.The actuator 20 is configured to raise and lower the maintenanceassembly 10 relative to the floor 24. Although a burnishing tool isillustrated in the Figures, it should be understood that the maintenanceassembly 10 may be configured to perform other types of maintenancetasks, such as sweeping and scrubbing, or a combination of maintenancetasks. As shown in FIG. 5, the maintenance assembly 10 includes arotatable driver 12 having a rotatable shaft 14 coupled to a drivermotor 16. The rotatable work tool for performing the work task is aburnishing pad 18 that is coupled to a rotatable driver 12. Themaintenance assembly 10 and the actuator 20 may be implemented by way ofa wide array of components and techniques, many of which have beendescribed in the aforementioned published patents and publications,among others.

[0040] Although the present invention and its advantages have beendescribed in detail, it should be understood that various changes,substitutions and alterations can be made herein without departing fromthe spirit and scope of the invention as defined by the appended claims.Moreover, the scope of the present application is not intended to belimited to the particular embodiments of the process, machine,manufacture, composition of matter, means, methods and steps describedin the specification. As one of ordinary skill in the art will readilyappreciate from the disclosure of the present invention, processes,machines, manufacture, compositions of matter, means, methods, or steps,presently existing or later to be developed that perform substantiallythe same function or achieve substantially the same result as thecorresponding embodiments described herein may be utilized according tothe present invention. Accordingly, the appended claims are intended toinclude within their scope such processes, machines, manufacture,compositions of matter, means, methods, or steps.

1. A surface maintenance machine for operation upon a floor surface,said surface maintenance machine comprising: a surface maintenance toolcoupled to the machine through a plurality of linkages which permit thesurface maintenance tool to be raised and lowered relative to thesurface maintenance machine into selective contact with the floorsurface; a spring assembly including at least one adjustable spring,said spring assembly being coupled to the surface maintenance tool sothat a spring force is transferred to the surface maintenance tool; anda selectively controllable actuator coupled to the spring assembly, saidactuator controlling a level of the spring force so that a controlledlevel of surface maintenance tool work is performed upon the floorsurface.
 2. The surface maintenance machine of claim 1, wherein theplurality of linkages comprises a four bar linkage device.
 3. Thesurface maintenance machine of claim 1, wherein the spring assembly iscoupled to at least one of the plurality of linkages.
 4. The surfacemaintenance machine of claim 1, wherein the spring assembly includes aspring retained within a spring housing.
 5. The surface maintenancemachine of claim 1, wherein the actuator is connected to the springhousing.
 6. The surface maintenance machine of claim 1, wherein theactuator is an electric actuator.
 7. The surface maintenance machine ofclaim 6, wherein the actuator is an electric linear actuator.
 8. Thesurface maintenance machine of claim 1, wherein the actuator is ahydraulic actuator.
 9. The surface maintenance machine of claim 1,wherein the spring assembly is coupled to the surface maintenancemachine in a generally parallel orientation relative to the groundsurface.
 10. The surface maintenance machine of claim 9, wherein thespring assembly is generally elongated and is coupled to the surfacemaintenance machine so that an elongated dimension of the springassembly is aligned generally in a direction of machine motion.
 11. Thesurface maintenance machine of claim 1, wherein the spring forcetransferred to the surface maintenance tool tends to lift the surfacemaintenance tool away from the floor surface.
 12. A suspension devicefor coupling a surface maintenance appliance to a surface maintenancemachine, said suspension device comprising: a plurality of linkagescoupled between the surface maintenance device and the surfacemaintenance machine, said plurality of linkages permitting the surfacemaintenance device to be selectively transitioned relative to thesurface maintenance machine between a plurality of positions; a springassembly having at least one spring, said spring assembly transferring aspring force to at least one of the plurality of linkages and thesurface maintenance device; and a controllable spring actuator inengagement with the spring assembly for selectively controlling thespring force being transferred to the surface maintenance device duringoperation.
 13. The suspension device of claim 12, wherein the pluralityof linkages comprises a four bar linkage device.
 14. The suspensiondevice of claim 12, wherein the spring assembly is coupled to at leastone of the plurality of linkages.
 15. The suspension device of claim 12,wherein the spring assembly includes a spring retained within a springhousing.
 16. The suspension device machine of claim 12, wherein theactuator is connected to the spring housing.
 17. The suspension deviceof claim 12, wherein the spring assembly is coupled to the surfacemaintenance machine in a generally parallel orientation relative to theground surface.
 18. The suspension device of claim 17, wherein thespring assembly is generally elongated and is coupled to the surfacemaintenance machine so that an elongated dimension of the springassembly is aligned generally in a direction of machine motion.
 19. Thesuspension device of claim 12, wherein the spring force transferred tothe surface maintenance tool tends to lift the surface maintenance toolaway from the floor surface.
 20. The suspension device of claim 12,wherein one of the plurality of positions of the surface maintenancedevice relative to the surface maintenance machine is a substantiallyperpendicular orientation relative to a normal operational position. 21.A vehicle for burnishing a floor surface, said vehicle beingtransportable across the floor surface during a burnishing operation,said vehicle comprising: a burnishing head including a motor drivenburnishing pad; a plurality of linkages coupled between the burnishinghead and the vehicle, said plurality of linkages permitting theburnishing head to be selectively transitioned relative to the vehiclebetween a plurality of positions; a spring assembly having at least onespring, said spring assembly transferring a spring force to theburnishing head; and a controllable spring actuator in engagement withthe spring assembly for selectively controlling a burnishing force beingtransferred to the surface during operation.
 22. The suspension deviceof claim 21, wherein the plurality of linkages comprises a four barlinkage device.
 23. The suspension device of claim 21, wherein thespring assembly is coupled to at least one of the plurality of linkages.24. The vehicle of claim 21, wherein the spring assembly is coupled tothe vehicle in a generally parallel orientation relative to the groundsurface.
 25. The vehicle of claim 24, wherein the spring assembly isgenerally elongated and is coupled to the vehicle so that an elongateddimension of the spring assembly is aligned generally in a direction ofvehicle motion.
 26. The vehicle of claim 21, wherein the spring forcetends to lift the surface burnishing head away from the floor surface.27. The vehicle of claim 21, wherein one of the plurality of positionsof the burnishing head relative to the vehicle is a substantiallyperpendicular orientation relative to a normal operational position.